The invention relates to a two-block concrete railroad tie for a fixed rail carriageway with an at least partially continuous reinforcement, which is exposed between the blocks and, after alignment, engages the sealing compound over a supporting layer, becoming anchored in it.
Such two-block concrete railroad ties with different types of continuous reinforcement have already frequently been proposed and are also on the market in different embodiments. Such a railroad tie, as well a method for installing a fixed rail carriageway using such railroad ties are described in the German Offenlegungsschrift DE 196 53 858 A1. For the installation, the concrete railroad ties, carrying the rails or auxiliary rails, are pre-mounted into a rail, adjusted with respect to position and height over the supporting layer, which usually is not reinforced, lean concrete layer and finally embedded in a sealing compound. Aside from the embodiments, in which part of the reinforcement protrudes from the bottom of the only partly concreted railroad tie blocks, as a result of which a particularly intimate anchoring of the railroad ties in the sealing compound is achieved, the proposal has also already been made in an older application to mold a placement concrete block, which protrudes downward beyond the reinforcement, to the underside of the concrete, which envelops the railroad tie block, for placing the railroad tie on the supporting layer. However, as with all railroad ties with pre-alignment, for which the sealing composition must also be brought in under the railroad ties, which are disposed at a greater or lesser distance above the supporting layer, the difficulty arises that a continuous, simultaneous casting of the railroad ties of a railroad tie grid is not possible and, instead, must take place section by section, since it otherwise cannot be ensured that the sealing composition fills up the space under the railroad ties and that bubbles cannot be formed by the air present there.
It is therefore an object of the invention to configure a two-block concrete railroad tie of the type named above such that a simultaneous casting of adjacent railroad tie sections and, with that, the casting of a rail grid in one step is possible without the danger of air inclusions.
Pursuant to the invention, the blocks are provided with a placement surface, which is shortened appreciably in the longitudinal direction and from which, at least at the front side, slanting side surfaces extend upward. Before the aligning, the placement surface initially serves for depositing the railroad tie directly on the supporting layer. After the alignment, the placement surface is connected by a layer of adhesive, which is about 2 to 8 cm thick, with the supporting layer. During the subsequent casting, it is no longer necessary to take care that the air below the railroad ties escapes since, after all, the adhesive layer is present here. Air can also not be collected at the sides, as is the case with constructions with the integrally molded placement concrete blocks, since the air can be displaced without difficulties over the slanted side surfaces. Because the side surfaces are inclined preferably an angle of 45xc2x0, the vertical forces are introduced advantageously into the supporting layer, optionally an open box plate, with a load distribution of 45xc2x0 over the carriageway plate. The slanted side surfaces shall be profiled rather encasement-smooth in order to have a better connection later on with the enveloping concrete.
The slanted side surfaces and the placement surface, which is shortened in the longitudinal direction of the railroad ties, are particularly advantageous for the introduction of the longitudinal iron rods into the fixed carriageway, that is, the longitudinal reinforcing iron rods which are aligned perpendicularly to the axis of the railroad ties, since these reinforcing iron rods do not need to be arranged relatively far apart by the blocks, as in conventional two-block concrete railroad ties. Because the surfaces are slanted, the longitudinal iron rods which are arranged immediately to the side of the blocks can lie much closer to one another than in conventional embodiments.
In a development of the invention, provisions can be made so that steep, oppositely inclined upper front surface sections adjoin the slanted, inwardly inclined side surfaces-the strong counter-conicity prevents the whole block being pulled out-in much the same way as they are conventionally present continuously from the upper side to the underside of the blocks, it being possible to dispose the upper front surface sections directly next to the support shoulders, so that a shortening of the blocks results once again overall. As a result of this additional reduction in the volume of the blocks of a two-block concrete railroad tie in accordance with the invention, the railroad tie is very much lighter and therefore can be handled better and that, in particular, because of the lower weight, rail grids of such two-block concrete railroad ties can be handled more easily and aligned over the supporting layer and glued to the latter.